Plate-type apparatus composed of shells for carrying out thermo-dynamic processes based on heat exchange between flowing fluids are already known in the art. Such apparatus are described e.g. in U.S. Pat. No. 4,497,689 the basic units of which are shells composed of spaced confining plates with fluid conducting passages therebetween. The significance of their employment consists in that any desired thermo-dynamic outputs of predetermined value are obtainable by selecting a suitable number of uniform shells. Thus, various apparatus can be composed of identic units which, in turn, may be made e.g. by automated robots in series production requiring but a few manufacturing operations.
A desired thermo-dynamic process such as evaporation or refrigeration is effected by fluids flowing in the passages of the shells and influencing each other through the heat conductive surfaces of the latter.
Circulation of the fluids is, as a rule, brought about by pumps outside the shells. Where fluid flow has to be effected inside hermetically and probably permanently closed shells as e.g. in refrigerators, the fluids are circulated by the action of heat. For such purpose the hermetically closed shells are provided with thermo-siphons which are energized by heat sources located in adjacent shells.
Thus, hitherto known plate-type apparatus of the above described kind operate exclusively by means of heat exchange between fluids without any interaction of their pressures which are left unexploited. Therefore, it seems desirable to provide means by which, in addition to heat exchanges between fluids, also their pressure changes are enabled to be exploited. As will be seen, such possibility permits, on the one hand, to simplify shelled thermo-dynamic apparatus and, on the other hand, to extend their field of employment.